Thermometer tube forming apparatus



July 4, 1961 J. L. CHANEY THERMOMETER TUBE FORMING APPARATUS 5 Sheets-Sheet 1 Filed Nov. 7, 1956 INVENTOR.

JOHN L. CHANEY ATTORNEYS July 4, 1961 J. CHANEY THERMOMETER TUBE FORMING APPARATUS 5 Sheets-Sheet 2 Filed NOV. 7, 1956 INVENTOR.

JOHN L. CHANEY ATTORNEYS July 4, 1961 J. L. CHANEY THERMOMETER TUBE FORMING APPARATUS 5 Sheets-Sheet 3 Filed NOV. 7, 1956 INVENTOR. JOHN L. CHANEY In ///vn/ hfl i ATTOR NEYS July 4, 1961 CHANEY 2,990,648

THERMOMETER TUBE FORMING APPARATUS Filed Nov. 7, 1956 5 Sheets-Sheet 4 FIG-2O 2 21 FIG-19 Q r I 12? 167 172 167 16s\ I r -165 164" mil INVEN TOR.

JOHN L. CHANEY BY M W wv qy ATTORNEYS July 4, 1961 J. L. CHANEY 2,990,648

THERMOMETER TUBE FORMING APPARATUS Filed Nov. 7, 1956 5 Sheets-Sheet 5 FIG-27 155 f 137 INVEN TOR.

JOHN L. CHANEY ATTORN EYS United States Patent 1 9 .6 THERMOMETER TUBE FORMING APPARATUS John L. Chaney, Lake Geneva, Wis. Filed Nov. 7, 1956, Ser. No. 620,837

'Claims.- ('Cl. 49-7) This invention relates to the manufacture of thermometer tubes or the like.

Thermometers as now manufactured and sold contain a temperature responsive and indicating liquid. This liquid is contained in an inner-temperature indicating passageway or bore of very small,,hair1ike, or capillary diameter. A liquid holding bulb is connected to this passageway at its bottom. The bulb holds approximately ten times as much liquid as the temperature indicating passageway, hence any small variation in the size of the bulb multiplies many fold its eflect on the temperature indications. A tube ordinarily is shaped with a magnifying front to magnify the airlike column of liquid, and a reflecting face ordinarily is included to aid in reading the column. The tube ordinarily is placed against a flat scale which indicates the temperature in degrees. It is desirable to flatten the bulb and to locate it to one side of the tube axis to present a continuously straight face adjacent the flat scale. This is desirable so the tube and bulb can be secured closely adjacent the flat scale, to permit the temperature to be accurately and easily read. The previous methods used in the formation of the bulbs at the bottoms of the tubes have required considerable individual skill and such human equation has resulted in great irregularity in the formation of the bulbs. The present invention overcomes the disadvantages in previous manufacture by eliminating reliance on such individual skill and results in much greater uniformity of production, effectively reducing the previous high volume of scrap.

The previous methods resulted in the formation of many different sizes or groups of bulbs. Each one of these groups required a different scale to be placed behind the tube. This was necessary because any change in the volume of the bulbwas magnified in the lineal travel of the thermostatic liquid in the hairlike temperature indicating passageway, since the volume of the bulb is approximately times that of the passageway. These tubes are matched to the necessary scale by first cooling the thermometer, without the scale, in ice and water, to mark the 32 \F. on the tube. Thereafter the tubes are heated to some other temperature such as-90" F. and a second mark is made. The distance between the marks establishes the class or group. With the previous methods, the variations were so great that approximately difierent groups of tubes, and 20 different scales were required. The present invention results in much greater uniformity of bulb size, and has materially reduced the number of groups of tubes and scales, to approximately 6, with a resulting saving in' time for sorting and selecting the tubes and scales and less wastage at the extremes.

Hence, an object ofthis invention is to provide an improved apparatus for sealing the ends of thermometer tubes and forming bulbs at the ends of such tubes with great rapidity and uniformity.

Another object of this invention is to provideapparatus in which a series of thermometer tubes are automatically sealed at their bulb forming end and bulbs are formed at such ends with great uniformity and rapidity.

Another object of this invention is to provide an ap- ICC paratns in which aseries of thermometer tubes are moved by an endless conveyor past a plurality of stations where the bulb ends of the tubes are sealed while being heated to a molten condition, and in which a gaseous medium under pressure is introduced into the open ends of the tubes while a mold is maintained at the bulb ends of the tubes to form and control the formation of the bulbs at these ends.

Further objects will become apparent as the description proceeds.

In the drawings:

FIG. 1 is a diagrammatic elevation of certain parts of a machine embodying this invention.

FIG. 2 is a top plan view, partly broken away, and enlarged, of the machine shown in FIG. 1.

FIG. 3 is an enlarged elevation of the elements adjacent the tube locating station of the machine.

FIG. 4 is a horizontal cross-section taken along the line 4-4 of FIG. 3.

FIG. 5 is an enlargement of a portion of FIG. 4.

FIG. 6 is a side elevation of some of the heating elements at one of the heating stations of the apparatus.

FIG. 7 is an enlarged end View of one of the burner elements shown in FIG. 6. V

. FIG. 8 is a cross-section of one of the tubes immediately after it has been subjected to the first heating operation.

FIG. 9 is a view, partly in elevation and partly in cross-section, showing the tube immediately after a further heating step which occurs at another station and during which the bulb end of the tube is initially sealed.

FIG. 10 is a side elevation of the tube and heating element in the final heating station.

FIG. 11 is an enlarged end view of the burner element of FIG. 10.

FIG. 12 is a view similar to FIG. 9, but showing a further sealing and melting action produced by the heating element of FIG. 10.

FIG. 13 shows the gaseous medium introducing elements of the apparatus at the bulb forming station and at the initial stage of operation.

FIG. 14 shows the elements shown in FIG. 13, but during a subsequent stage Where the apparatus has surrounded the open end of the thermometer tube.

FIG. 15 shows a portion of the elements shown in FIG. 14 at a further subsequent stage of operation where the sealing sleeve has compressed and sealed itself around the end of the thermometer tube.

FIG. 16 is an enlarged cross-section taken along the line 1616 of FIG. 14.

FIG. 17 is an enlarged cross-section taken along the line 17-17 of FIG. 15.

FIG. 18 shows the'thermometer tube at the time when the initial enlargement has been formed at the molten bulb end of the tube.

FIG. 19 is an elevation of the elements at the bulb forming station of the apparatus.

. FIG. 20 is 'an'efilarged vertical cross-section of the mold actuating mechanism in closed position.

FIG. 21 is an enlarged cross-section taken along the line 2121 of FIG. 20.

FIG. 22 is an enlarged elevation of the left hand element of the mold shown in FIG. 20.

FIG. 23 is afront elevation of the right hand element shown in FIG. 20.

FIG. 24 is a vertical cross-section taken along the line 24-24 of FIG. 21.

FIG. 25 is a vertical cross-section of the bulb end of the finished tube, taken along the line 2525 of FIG. 26.

FIG. 26 is a cross-section taken along the line 26--26 of FIG. 25.

FIG. 27 is a diagram of the air flow connections in the apparatus to show how many of the elements in the apparatus are actuated.

Referring to the drawings which showa preferred embodiment of the invention and initially to FIGS. l and 2, an intermittently movable or rotatable endless conveyor, such as circular table 30, is rotatably mounted on a stationary housing 31 and apron 32 which are supported on a pedestal 33. Motor 34 rotates a shaft 35 through the medium of an adjustable speed belt drive 36, and intermittently drives or rotates the table 30, so the tube holders 37 are moved to, and pause at, each of a plurality of stations adjacent the conveyor 30. For example, the shaft 35 drives the worm gear 38, which in turn operates a Geneva drive, not shown, contained in the housing 31 which produces the intermittent rotation of the table 30. Suitable gearing in the housing 31 automatically rotates the shaft 39 one revolution during each pause of the table 30, but the shaft 39 preferably does not turn while the table 30 is moving. The shaft 39 carries a cam 40 for controlling certain operations which take place during the pauses of conveyor 30, in a manner more fully to be described.

The holders 37 are equally spaced around the periphery of the table 30, for example, at every 20. The holders 37 serially stop at each of the stations adjacent the conveyor 30, and certain operations take place at these stations which will be later described. Open ended straight tubes 80 are placed in the tube holders at station 41 preferably in vertical positions. The lower or bulb ends of the tubes are heated, melted and sealed at certain of the stations, by one or more heating means. For example, at station 42 a pair of burners 43 and 44 (FIG. 6) may heat the sides of the bulb end 45 of the tube to a temperature of about 500, and the tube end becomes partially molten as indicated in FIG. 8. At station 47 a second set of opposed burners, similar to those shown in FIG. 6, are placed at a different angle from the burners of station 42, and these burners further heat the bulb end of the tube to a temperature of about 800", such as to cause the glass to soften and initially seal the end of the tube as indicated in FIG. 9. At station 48, a vertical heater, as shown in FIG. 10, heats the bottom of the bulb end 45 by the upwardly directed flame 49, from the burner 50, and heats the bulb end of the tube to a still higher temperature of about 1500 to the proper molten condition, as indicated in FIG. 12. At station 51, a gaseous medium under pressure is introduced into the unsealed ends 105 of the tube and a clamping mold at this station, later to be more fully described, controls the formation of the bulbs at the lower ends of the tubes to maintain them of uniform size and shape. The tubes then travel through several stations where the tubes gradually cool and harden until they reach station 52. They are released at station 52, and drop into the chutes 53 and slide into the bin 54. i

The tube loading operation which takes place at station 41 is more fully described by reference to FIGS. 3, 4 and 5. Each of the holders 37 includes a column 60, carried by base 61 secured to the table 30. A carriage 62 is secured to the column in a vertically adjustable manner by the screws 63. The normally stationary clamp member 64 is horizontally adjustably secured to carriage 62 by means of screw 65 which passes through a narrow slot 66 in the clamp 64. The slot 66 is narrow enough to permit the outer face of clamp 64 to be engaged by the head 67 of screw 65. The clamp member 64 also slides in grooves 68 and 69, formed in carriage 62. The movable clamp member 70 is horizontally slidable with respect to the stationary clamp member 64. To this end, the pin 71 is secured to the clamp member 64 and guides the narrow slot 72 in clamp member 70. The pin 71 carries one end of spring 73, the other end of which is secured to pin 74, which is secured to the movable clamp member 70. The clamp member 70 is provided with a right angled flange 75 behind which the operator may place his fingers to pull the clamp member 70 toward himself as indicated by the dotted lines in FIG. 4. The large slot 76 in clamp member 70 maintains the clamp member 70 in horizontal position, in cooperation with the head 67 of screw 65. This is aided by the pin 71 and narrow slot 72 to maintain a straight-line movement of clamp 70. When the clamp member 70 is pulled toward the operator a thermometer tube 80 is inserted between the jaw member 81 of stationary clamp64 and the spring clip member 82 which is carried by the flange 75 of movable clamp 70. The jaw member 81 includes the upper forked jaws 83 and the lower forked jaws 84 which have converging faces 85 which engage the converging surfaces 86 of the tube 80. The faces 86 of the tube, in combination with the curved surface 87, form a magnifying lens which enlarges the column or temperature indicating passageway 88 of the glass tube 80. A reflecting surface 89 is formed within the tube 80 behind the column 88, or it may be placed on the back face 90 in the form of a reflecting coat of paint.

The locking of the tubes 80 in the tube holders 37 is preferably a manual operation because of the irregular cross-section of the tubes 80, as shown in FIG. 5.

Means are provided for longitudinally locating the tubes 80 in the holders 37. Such means may take the form of normally stationary, but adjustably mounted table 91, mounted at station 41. For example, a vertical pin 92 is secured to the housing 31 by welds 93. A horizontal pin 94 is vertically adjustably mounted on vertical pin 92 by a suitable clamp member 95. Table 91 is horizontally adjustable on the pin 94, being slidable thereon but being normally clamped by the screw 96.

To place the tubes 80 in the holders 37, the operator pulls the flange 75, FIG. 4, to the dotted line position, inserts the tube 80 with the smaller side 87 toward the center of the machine, as shown in FIG. 5, and then releases the flange 75, thereby to lock the tube 80 between the jaws 83, 84 and the spring clip 82. Before releasing the flange 75, however, the operator allows the tube 80 to ride on top of the table 91, so the tube 80 is properly longitudinally and vertically located before being clamped in the holder.

After leaving the loading station 41, the tubes pass through the heating zone comprising one or more stations 42, 47 and 48. At station 42, opposed burners 43 and 44, as shown in FIG. 6, direct the flames against the sides of bulb end 45. The pause at this station is suflicient to raise the temperature of the tube end to about 500 R, which produces a partial melting of the end as indicated in FIG. 8. Thereafter the tube passes to station 47 where a second set of opposed burners, also as shown in FIG. 6, direct flames 100 from a different angle, completely to heat all sides of the tube end and raise the temperature to about 800 F., to produce an initial sealing thereof as shown in FIG. 9. The tube then progresses to station 48 where the vertical burner 50 of FIG. 10 directs flame 49 vertically up against the bottom of the tube end 45 and completely melts and seals the same in a slightly globular form, as shown at the bottom of FIG. 12.

The tubes then progress to station 51 where a combined blowing and molding operation forms the bulb at the bottom or bulb end of the tube as more fully described with respect to FIGS. 13 through 26.

6 Means in the form of a thermometer tube glass feeding device is provided at station 51 for feeding a gaseous medium under increasing pressure into the unsealed, open end of the tube 80. For example, the solid outer sleeve. 106 is in alignment with the" tube end 105 (FIG. 13) whensuch end pauses at station 51. The

outer sleeve 1'06. holds a flexible contractable inner sleeve 107 formed of a suitable elastomeric material such as rubber. The sleeve 107 has an axial opening 107a of slightly greater diameter in an uncompressed condition than the greatest cross sectional dimension of the end 105 as shown in FIG. 16. The sleeves 106 and 107 are in their upper positions above tube end 105 as shown in FIG. 13. Sleeves 106 and 107 are then moved to their lower positions around tube end' 105 as shown in FIGS. 14 and 15. In FIG. 14 the sleeves 106 and 107 have been placed around tube end 105, but the sleeve 107 has not been contracted and sealed around the tube end 105. In FIG. 15 the flexible sleeve 107 has been contracted and sealed about the end 105 by a downward movement of the end 112 of the solid inner sleeve 108. The sleeve 108 formsa gas conduit 110 continuously connected to the hose 109. V The gaseous medium or air coming from the hose 109 is at very low pressure when it reaches the conduit 110 of the' inner sleeve 108, since there is a free flow of to the atmosphere at this time. However, after the sleeve 107 has been sealed around the tube end 105, and the air continues to' be forced into the tube 80, the pressure in the hose 109 and the passageway 110 gradually rises sufiiciently high to form the bulb at the bottom of the tube 80 and also to trip a mechanism for actuating the mold as hereinafter more fully to be described. The sleeve 107 constitutes a thermometer tube gripping portion arranged to receive the open end 105 of the tube for theapplication of gas pressure thereto from the hose 109.

Further details of the contracting action of sleeve 107 are now described. The outer sleeve 106 hasa flanged outer sleeve end 111 defining a thermometer stern inlet opening 111a. The inner sleeve 108 has an inner sleeve end 112 with a washer 113 with an opening 113a. The flexible sleeve 107 is longitudinally held between the ends 111 and 1112. The outer sleeve 106 has an upper flange 1 14 which is adapted to come in arresting engagement with the upper surface or abutment 115a of the bushing 115, when the sleeve 106 is in its lower position, as shown in FIGS. 14 and 15. A compression spring 116 is placed between the flange 1114 and the bushing support 117. The spring 116 is of suflicient strength to move the sleeve 106 to its upper position when the plunger 118 is not pushed downwardly. However, the strength of the spring 116 is not sufiicient to cause any substantial contraction of the sleeve 107 while the plunger 118 is pushing the sleeve 108 down from the position shown in FIG. 13 to that shown in FIG. 14 and therefore the sleeve 107 is lowered over the end 105 without touching the tube 80. The opening 113a in the washer 113 and the openingl lla in the flanged end 111 have substantially eq ual diameters one to the other as shown in FIGS. 13 and 1 4 in order that the compression of the sleeve 107 by the sleeve 108 does not result in the extrusion of the elastomeric material through the opening 111a any more than through the opening 113a. By this means vertical displacement of the tube 80 is avoided. After the sleeve 106 reaches the position shown in FIG. 14 with the flanged-.14 against the bushing 115, the plunger 118 and inner sleeve 108 continue their downward movement sufficiently to squeeze the flexible sleeve 107 longitudinally as shown inFIG. l5 and thus contract and seal it around the tube end 105. The plunger 118 is pushed down and moved up by the pneumatic piston construction 120 shownin FIG. 1. The spring 116 aids in pushing the plunger 118 up. The plunger 118 is pushed down by air under pressure from the conduit or hose 121 under a controllater to be described.

Referring to-FIGS; 13 through 18, at the proper point in the cycle air or other gaseous medium is fed under pressure through the h'ose109 and passageway 110 into the inner temperature, indicating pasageway 88. of the glass tube80. Since there is no leakage oi air to the atmosphere after the sealing action shown in FIG. 15 around the tube 80, the air inpasageways 109, and column 88 gradually builds up in pressure, increasing to the point where a small enlargement 125, FIG. 18, is formed within the molten end 45 of the tube 80. This gradually increasing pressure of the air causes the limiting or clamping mold 126, 127 (FIGS. 19-26) to surround and limit the bounds of the enlargement at the bottom end of the tube and controls the formation of the bulb causing it to take the shape shown in FIGS. 25 and 26 in a manner more fully to be described.

The actuation of the mold 126, 127 in response to the gradually increasing pressure in the passageways 109, 110 is performed by the elements and connections shown in FIG. 27. The tube 109 receives air under pressure from the conduit 130 and the manually adjustable valve 131. Conduit 130 has air under about 30 p.s.i. pressure, for example. However the valve 131 is turned toa throttling position to limit the rate of air flow which is fed to the pipe 109, to produce the gradually increasing pressure heretofore described. Another pipe 132 is connected to the pipe 109 and is connected at its other end with the pressure responsive switch 133. The air from the pipe 132 passes through the hand adjustable throttling valve 134 to bellows 135, and gradually compresses spring 136, and moves shaft 137'to close the normally open micro switch 138, when a predetermined pressure is reached in the bellows and pipes 109 and 132. The closing of switch 138 closes the mold 126, 127 as more fully hereafter described. When the pressure is relieved in the bellows 135, the micro switch 138 opens and opens the mold 126, 127.

The electrical supply passing through the micro switch 138 is transmitted through the wire 139 to a solenoid valve 140 which opens upon receiving electric current and permits air under pressure to pass from the pipe 141 to the pipe 142, to actuate the pneumatic air motor 143. The air motor 143 actuates a mechanism 144 which causes the mold parts 126 and 127 to come together to the position shown in FIG. 20. When the valve 140 is de-energized, by the opening of switch 138, the air in pipe 142 is allowed to escape at valve 140 providing for the retraction of the motor 143 through the spring 160 which returns the mold 126, 127 to open position.

The closing of the mold 126, 127 to the position shown in FIG. 20 takes place simultaneously or immediately after the formation of the small enlargement 125, shown in FIG. 18. Thereafter the continued pressure of the air entering through the pipe 109 causes the small enlargement 125 of the FIG. 18 to form into the completed bulb 145 shown in FIGS. 25 and 26.

The mold half 126 has an offset 146 which cooperates with the straight face 147 of the mold half 127 to form the bulb 145 as shown in FIG. 26, in line with the passageway 88, but out of line with the central axis of the tube 80. This produces the straight face 148 on one side. of the tube and produces the offset 149 on the other side of the tube. The straight face 148 of the tube permits it to be placed against the usual flat temperature indicating scale, not shown, without any danger of breakage or distortion. The mold halves 126, 127 have circular cups 150 and 151 which form the circular rim 152 of bulb. 145, shown in FIG. 25.

Referring particularly to FIGS. 19 and 20, the opera.-v tion of mechanism 144, which actuates the mold halves 126, 127, will now be described in further detail. The pneumatic piston mechanism 143 has a plunger 155 which engages another plunger 156 mounted to move axially through the bearings 157 and 158. A pin 159 receives one end of the compression return spring 1*60, the other end of the spring 160 abutting the bearing 158. The plunger 156 is moved to the left (in FIG. 19) by the plunger 155, and it is returned by the spring 160 when the pressure is relieved from the pneumatic mechanism 143'.

The mold half 126 is carried by the pivoted lever 161, while the mold half on 127 is carried by the pivoted lever "162. The levers 161 and 162 are pivoted around the pin 163 by their respective axially offset hinge cylinders 164 and 165. The levers 161 and 162 are connected by links 166 and 167 with the plunger 156 by any suitable construction 168 which permits the links 166 and 167 to pivot about the pins 169 and 170. The links 166 and 167 are also pivoted at 171 and 172 to their respective levers 161 and 162. When the plunger 156 is moved to the left, FIG. 19, the mold halves 126 and 127 are brought together, whereas when the plunger 156 is moved to the right, the halves 126 and 127 are separated.

The mold 126, 127 is supported by any suitable mount. For example, a plate 175 is mounted on the housing 31 by means of the screws 176, which also conveniently support valve 140, as shown. The horizontal supports 180 and 181 are horizontally mounted and joined together by bolted construction 182.

After the bulb forming action is completed at the station 51, each tube 80 travels in a clockwise direction, as viewed in FIG. 2, through a plurality of other stations where the tubes pause and cool. Eventually they reach station 52 where the tubes are released to fall into the chute 53 and bin 54. Tube releasing mechanism for moving the clamp 70 outwardly may be used. For example, plunger 185 is moved periodically outward and inwardly by the pneumatic piston construction 186, which includes a return spring construction, not shown, for retracting the plunger 185 when the pneumatic pressure is released from the pipe 187 after the thermometer tubes are released.

The pipes 121 and 187 are fed by a vertical stationary pipe 188 (FIG. 1) which passes up through a hollow supporting column 189, which also supports the horizontal central platform 190 for supporting tubes to be loaded at station 41 and for any other purpose which may be desired. The automatic actuation of the clamp 70 radially outward permits the tubes to fall from the holders 37 at station 52.

The pneumatic system for operating the various parts of the machine is diagrammatically indicated in FIG. 27. For example, the air tank 200 has air maintained at any suitable pressure by means of the pumping mechanism 201 which has the usual presure responsive switch for automatically maintaining the pressure in the air tank 200 at 60 p.s.i., for example, as is readily understood. A conduit 202 leads to the automatic pressure reducing valve 203, which may be manually adjustable to any desired pressure reduction by means of the knob 204. The valve 203 reduces the air passing through it to a pressure of about 30 p.s.i., for example, when it enters the conduit 130. This pressure is indicated by the gauge 205. The manual throttling valves 131 and 134 may be adjusted to throttle the flow of air to reduce the pressure practi cally to atmospheric pressure when the end of passage 110 is open, as in FIG. 13, and to obtain the desired gradual pressure increase in pipe 109 when passage 110 is sealed to tube 80, FIG. 15, as has been previously described. The valve 134 may be adjusted to increase or delay the responsiveness of the bellows 135 with respect to the rise in pressure in the pipes 109 and 132.

Another pipe 207 receives air at 60 p.s.i. from the tank 200 and feeds it to the automatic pressure reducing valve 208, which is manually adjusted at 209 and feeds air at 30 p.s.i., for example, to the pipe 210, this pressure being indicated at the gauge 211. The air from pipe 210 passes the manually adjustable throttling valve 212, which feeds the air to the pipe 141, solenoid valve 140, pipe 142, and piston actuator 143. The throttling valve 212 may be used to regulate the responsiveness of the piston actuator 143 so that the closing action of mold 126, 127 may be delayed more or less as desired. The valve 140 and the actuator 143 constitute mold operating means operable upon a signalto close the mold halves 126 and 127 about the sealed end of the tube.

Adjustable time delay means is provided by the adjust ment of the relative time delays produced by the manual throttle valves 131, 134 and 212, and by the adjustable automatic valves 203, 208 and 216, to enable the operator to calibrate the machine to obtain the proper timing of the closing of the mold 126, 127 in relation to the time of formation of the small enlargement shown in FIG. 18. The valve 134, the bellows 135 and the switch 138 constitute time delay means connected to apply an electric signal to the valve 140 of the mold operating means for closing the mold subsequent to the application of gas pressure to the thermometer tube through the conduit 110. It is important to have the mold 126, 127 out of contact with the bulb end until after the formation of enlargement 125, to avoid any chilling effect on the bulb end by the mold prior to the formation of the enlargement 125. Thereafter it is important to have the mold clamp around the bulb end before the enlargement has been blown to its maximum volume, since this permits the mold halves 126 and 127 to come completely together to present an identical volume limit to each expanding bulb. In this manner great uniformity of bulb size is obtained. The adjustment of air flow made possible by the manual adjustment of these valves enables the operator to obtain great accuracy in the relative timing of the initial bulb enlargement of FIG. 18 and the quick closing of the mold immediately thereafter and before the bulb has reached its correct maximum size.

Another pipe 215 receives air at 60 p.s.i. from the tank 200 and feeds it to an automatic pressure reducing valve 216 which is adjustable at 216a and which feeds air to the pipe 217 at 22 p.s.i., for example. This pressure may be indicated by the gauge 218. The pipe 217 feeds air to the periodically actuated valve 219, which opens when the lever 220 is moved to the left by the hill 40a, cam 40, and which closes when the lever 220 is moved to the right by the spring 221 after the hill of the cam has passed. The valve 219 feeds the pipe 222 which is connected to the vertical pipe 188 heretofore described and which feeds the pipes 121 and 187.

The operation, briefly summarized, is as follows: The endless conveyor, or circular table 30, is intermittently rotated by a Geneva drive in a clockwise direction as viewed in FIG. 2. The table 30 carries a plurality of tube holding mechanisms 37 conveniently spaced every 20, for example, around the table 30. Straight lengths of unsealed glass thermometer tubes 80, having a crosssection as shown in FIG. 5, are conveniently stacked on the stationary platform 190 adjacent the station 41. The operator takes these tubes from the platform 190 and loads them individually on each holder 37 at station 41 in the manner indicated in FIGS. 3, 4, and 5. He places his fingers behind the flange 75 and pulls the clamp 70 toward himself, as indicated in FIG. 4, and places the tube length 80 between the spring clip 82 and the jaw members 83 and 84. He then releases the flange 75 and the clamp 70 moves leftward and secures the tube 80 in proper position by means of the spring clip 82, this tube having been vertically adjusted to the right height by engagement at its lower end with the platform 91. Thereafter the tubes are carried in progressive movements and pauses past the various stations adjacent the rotating table 30. Eventually the tubes pass the required heating means, such as one or more gas burners as at stations 42, 47 and 48. The burners at stations 42 and 47 are horizontally opposed to each other as indicated in FIG. 6 and have different directions as indicated in FIG. 2. The burner at station 48 is a vertical one as indicated in FIG. 10 and heats the bottom of the tube 45. While at station 42, the tubes 80 are heated to 500 F. at their lower ends 45 to produce an initial melting action, as indicated in FIG. 8. They are heated to 800 F. at station 47 and are slightly sealed at their lower ends, as

indicated in FIG. 9. At station 48, they are heated to 9. 1500" F. and the bottom 45 of the tubes 80 become molten to the desired degree, as indicated in FIG. 12, and are in a condition to be blown at station 51.

At station '51, the operations indicated in FIGS. 13 through 26 are performed. First the hill 40a of cam 40 (FIG. 27) opens valve 219 and feeds air at 22 psi. to the pipes 121 and 187. In the meantime, air under 30 lb. pressure has been continuously fed to the pipe 130 and past the throttling valve 131, so that is allowed to leak slowly into the pipes 109 and 132. As long as the elements shown in FIG. 13 are in that position, the air from pipe 109 falls to practically atmospheric pressure, due to the fact that the lower :end of passage 110 is open to the atmosphere as at FIG. 13. However, when the valve 219 of FIG. 27 is opened the plunger 118 is pushed down by the air pressure impulse in pipe 121 and this pushes the sleeves 108 and 106 to the positions of FIGS. 14 and 15 respectively. This causes the flexible sleeve 107 to be sealed around the open end 105 of the tube 80 and to permit the air under pressure to be fed from the pipe 109 into the bore or passageway 88 of the thermometer tubes 80. The air in pipe 109 gradually increases in pressure after the position of FIG. 15 has been reached, and increases the pressure in pipes 109 and 132 until the pressure responsive switch 133 closes the micro-switch 138 to energize the solenoid valve 140. The valve 140 opens when energized, and permits air under pressure to pass through the pipe 142 to the pneumatic plunger mechanism 143. When this occurs the plungers 155 and 156 are moved leftward as viewed in FIG. 19 (or rightward in FIG. 27), thus moving the mold elements 126 and 127 from the open position shown in FIGS. 19 and 27 to the closed position shown in FIG. 20. During these operations, the lower end 45 of the tube 80 has had a small enlargement 125 (FIG. 18) blown in it which is then further enlarged within the confines or bounds of the mold 126, 127 to form the bulb 145 (FIGS. 25 and 26) which has a circular cross section as viewed in FIG. 25 and an offset construction as shown in FIG. 26. Hence, one face 148 (FIG. 26) of the tube is continuously straight, so that this face may be placed against the usual flat temperature indicating scale.

Subsequent to the opening of the elements 126 and 127 of the mold, the tubes leave station 51 and continue through a plurality of undesignated stations which permit the tubes to cool until they finally reach the unloading station 52 where they are released from the holder by the action of pneumatic plunger mechanism 186 which is temporarily energized when the bill 40a of cam 40 opens the valve 219 as previously described and sends a pressure impulse to plunger 186. The plunger of mechanism 186 is spring retracted when the valve 219 is closed. The tubes drop by gravity at station 52 into the chute 53 and slide into the bin 54.

This automatic procedure eliminates the many irregularities in bulb sizes caused by the human equations of previous methods, and produces bulb constructions of unusual regularity in size, and in large quantities, with a minimum labor requirement.

While the form of the embodiment of the invention as herein disclosed constitutes the form now preferred, it is to be understood that other forms may be adopted, which come within the scope of the claims which follow.

What is claimed is as follows:

1. In a machine for forming thermometer tubes, in combination, an intermittently movable conveyor, a tube holder on said conveyor serially movable to stations adjacent said conveyor and adapted to hold a tube with a molten bulb-forming end and with an open other end, an uninterrupted source of gas under pressure at one of said stations, means connecting said source to said open end of a. tube at said station for introducing gas into said tube to form a small enlargement in said molten bulbforming end free of chilling effect of a mold, a clamping mold having portions closeable about said enlargement 10 to define the formed shape thereof, mold operating means operatively connected to said mold portions and operable upon a signal to close said portions about said enlargement, and time delay means connected to apply a signal to said mold operating means for closing said portions subsequent to the formation of said enlargement.

2. A tube blowing device comprising, a tube holder arranged to support a thermometer tube with an open end and with a molten sealed end, a thermometer tube gas feeding device including a gripping portion thereon arranged to receive the open end of said tube for the application of gas pressure thereto resulting in the formation of an initial small enlargement on said molten end free of chilling effect of a mold, a clamping mold including halves movable about said molten end to define the shape of a bulb formed thereon, mold operating means operatively connected to said mold halves and operable upon a signal to close said mold halves about said sealed end, and time delay means connected to apply a signal to said mold operating means for closing said halves subsequent to the application of said gas pressure through said feeding device.

3. In a thermometer tube blowing device for forming an enlarged bulb at a molten end of an unsealed thermometer tube, the combination comprising a source of gas under pressure, a gas conduit connected to said source, means applying said conduit to the unsealed end of said thermometer tube, a clamping mold operable when closed to define the limits of the bulb formed at said molten end by gas from said conduit, controllable mold operating means for closing said mold about the molten end of said tube, and pressure responsive means having a connection to said conduit and to said mold operating means for the actuation of said mold operating means at a predetermined point in the pressure build-up subsequent to the initial formation of the bulb by gas from said conduit.

4. In a thermometer tube blowing device for forming an enlarged bulb at a molten end of an unsealed thermometer tube, the combination comprising a source of gas under pressure, a gas conduit continuously connected to said source for the discharge of gas therefrom, means applying said conduit to the unsealed end of said thermometer tube, a clamping mold operable when closed to define the limits of the bulb formed at said molten end by gas from said conduit, a' pneumatic mold motor operated by gas from said source for closing said mold about the molten end of said tube, and pressure responsive means having a connection to said conduit and to said source and arranged to apply gas therefrom to said motor for the actuation of said motor at a predetermined point in the pressure build-up subsequent to the initial formation of the bulb.

5. In a thermometer tube blowing device for forming an enlarged bulb at a molten end of an unsealed thermometer tube, the combination comprising a source of gas under pressure, a gas conduit connected to said source, means for applying said conduit to the unsealed end of said thennometer tube, a clamping mold for defining the limits of the bulb formed at said molten end by gas from said conduit, solenoid controlled mold operating means for clamping said mold about the molten end of said tube, and pressure responsive switch means responsive to the pressure in said conduit at said thermometer and having an operative electrical connection to said mold operating means for the delayed actuation of said mold operating means subsequent to the initial formation of the bulb by the gas from said conduit.

(Other references on following page) 11 UNITED STATES PATENTS Brosehart Oct. 15, 1918 Stewart Feb. 11, 1919 Hofistetter et a1. Feb. 10, 1920 White Mar. 16, 1920 Leiman June 8, 1920 Quackenbush et a1. Mar. 31, 1925 Brown et a1. June 1, 1926 Sunderlin July 12, 1927 Meyer Jan, 15, 1929 10 12 Chaney Feb. 24, 1931' Meyer Nov. 3, 1936 McGowan Oct. 11, 1938 Kimble et a1. Dec; 31, 1940 Palmer et a1. Dec. 29, 1942 FOREIGN PATENTS Germany June 9, 1939 Great Britain Mar. 2, 1928 

